Partial products mechanism



June 14, 1949. R. E. B11-NER PARTIAL PRODUCTS MECHANISM 7 Sheets-Sheet 2 Filed Nov. 13, 1945.

June 14, 1949. R. E. BITNER 2,473,466

PART IAL PRODUCTS MECHAN I SM Filed Nov. 13, 1945 '7 Sheets-Sheet 5 HG2, Li

zl r 33 mmm-m y INVENTOR June 14, 1949. R. E. BITNER 2,473,466

PARTIAL PRODUCTS MECHANISM Filed NOV. 13, 1 .945 7 Sheets-Sheet 4 INVENTOR June 14, 1949. R. E. BITNER 2,473,466

PARTIAL PRODUCTS MECHANISM Filed Nov. 13, 1945 '7 Sheets-Sheet 5 l I l c INVENI 0R June 14, 1949. R. E. BITNER PARTIAL PRODUCTS MECHANISM '7 Sheets-Sheet 6 Filed Nov. 13, 1945 ULTPLCAND THOUSANDS MULTIPLIER EQE | l I l l I l s l r I :Qian #im 'IIL l I I I I I I l I I L L L man wam hun msm mfv mi. but wxv mum mxn him Ogm` msm mnu #im www INVENTOR June 14, 1949.

R. E. BITNER PARTIAL PRODUCTS MECHANISM Filed Nov. 15, 1945 7 Sheets-Sheet '7 FIG. IO

SENSING UNIT PUNCH GARD MULTIPLYING NTEGRATORS UNITS AND ACCUMULTOR UNITS Z 3 4 5 MULTlPLICAND 6 7 8 9 MULTIPLIER PRODUCT-0159 2o 205 INVENTOR ina multiplier andmake them availablev at sub- Patented `lune 14., 1949 ori-*ica PARTIAL PRODUCISMECHANISM V M Ralph Bitner, Roslyn, N. Y. Application November 13, 1945, Serial No. 628,038

7 Claims. (Cl. 235-61) .This invention relates vto a mechanism fory contain components that are not dependent upon obtaining `a series of partial yproducts from the small tolerances nor ne adjustments to pro. digits oi a multiplier -and multipl-icand. It more duce an accurate result. particularly relates to the details of-construction n Another object of the invention is to provide ot mechanisms which con-tain the multiplication 5 afmechanism which will be capable of long and table asa part of theirstructure and which are continued use without the necessity of Y repair tothe used as a component part of fast-operating and adjustment. multiplying machinesw While the invention is One feature of the invention comprises a mulsubjectto a wide range of applications. it is esif l'liplyil'lg` unit fOr producing the product 0f two peciallyl suited-for use in punched card systems 1o digits and comprises a plurality voi nine multiplier and will be particularly described in that conrods movably mounted in parallel relationship. motion l. l y l also a plurality of nine multiplicand rods mount- True multiplying machines, as distinguished edjjil parallel relatiOnShip, each oi the rods from computing machines-using repeated addiis designated by a digit from one to nine. A plug, tion, are nctrnew 0ne prior machine employs a 15 rality of electrical contact fingers are secured series of seventeen multiplier plates for each deto each multiplier rod and Ya plurality of Contact nomlnational order `to derive the partial prodlugs are secured to each multiplicand rod. Acuots, Kand a plurality of stepped cups forintetuating means are provided so that any desiggrating the partial products to obtain the final :n hated-multiplier rod may be moved to a posiproduct. Because of; the many mechanical move- 2U tion where contact may Joe made with the contact ments linvolved the vspeed o1 this machine is fingers and actuating means are also provided limited to twenty punched cards per minute. so'that any designated multiplicand iroel may belv .Another prior vmachine uses a series of commoved to a position Where contact may be made mutator rings cut in acordance with the m-ulti-V a with the contact lugs. The lugsand lingers are plication table. A plurality Aof mechanical 25 soI 'disposed' that they willi'make contact with cultches operatedifferential accumulators to in--fy each other only at one `place and that place tegrate the partial products The multiplicand represents the product of the designated multi--V lS Il'lllltlpl-ifbel` byy Each digit in the multiplier plierdigit by the designatedmultiplicand digit.v Separately. `hence the speed is kept down to .it Suitable electromagnetic means are `provided to twenty cardsper minute.` e v 30 transmit-mbe product oi the two digits to an Still another prior machine multiplies a-multiintegrator. 1 f l i f plicand, sensed from acardyby amultiplier which Allume-'r fem-,ure 0f the invention `(-,omprLi-,g is sensed byielectrical contact ngersas the card" the provision ofa multiplying unit foreach pair' is movedlthroush fil-sensing chamber. The 1111116"Y 'it off-digits selectedn from thei multiplier and mu1ti` of transit deterrriines the time a clutch is in 35 piiandfy Actuatinp mean-s are controlled by' Operative-contact towresisterthe partial products esem denominational order in the multiplier to intworaccumulatorsone for the units'digits and actuante a selectedA number ofthe lmultiplying` Unefffthe-tens dlglts This machine 150011- units and aotuatlnie means are also controlled Sidefablyf'fster menthe Ones enumerated above "t bye-reach'denominationaiioraer in the multipli-A butis `limited vby small tolerances; accurati' #0i-i 40 Cami to. actuate a seIectednumber of muitipiyadjustment,and` dependable contacts through mgwimits whereby eachldigit *in the multiplier' the Card While it 1S in mtlnf e ispaired witneacii digit in the muitipiicand to" VOne of the fobjects fof the invention, ithereforef mute allimulq-,fplymg .unit .and derive all the is to provide a partial products mechanism which' il pag-tia] pmdues' remi-,mg from the multiplica. substantially avoids one ormore oi the limita- 45 tion- 01 the twd numbers: ff tinf he P1101 m mamme* For a tetternnderstandin of the resent -Another object of theinvention to provideA imehmom. m'gthr `mutiJ1-heft .and furur. obp; a mechanism which will derive all the' partial .v l

, l Jects thereof, reference is had to the folio-wingr rncn dlal description taken in connection with the accorti-S g l p p pai-lying drawings and its scope will be pointed stantiiallly-` the instante the numbers are sensed.m out the appended claims- Another object ot'thelinvention is toprovide'af Fig.- 1 represents a plan View 0f multipli/ln! partiallproducts'mechanism Vfor a punched car-d1" if unit' i multiplier which' will cooperate with an inte-55 -Fig 'ZfS Schematic diagram of connections gratorrto multiply a ten'dig-itmultiplicand Lby af offtheemultiplying unit, battery, and Seventeen tenfdigi-tll-multiplier at the rate of one hundred electromagnets. i l i 1 cardszpereminutc. =f 1- i i Figi Bis-an enlarged plan view of one corner o!V lStill anotherobj-ect -oftheinvention istovpro-- the multiplying unit showing two rods in their l" vide a partial products mechanism which will 60 actuated position.

Fig. 4 is a sectional drawing of the unit in Fig. 3 taken along line 4 4 of that ligure.

Fig. 5 is a sectional drawing of the unit in Fig. 3 taken along line 5-5 of that gure.

Fig. 6 is a side View of the multiplying units set up in position where the multiplier and multiplicand digits can actuate the designated rods.

Fig. 7 is a detailed view of a spring unit used in Fig. 6.

Fig, 8 is a sectional drawing of the mechanism shown in Fig. 6 taken along line B-G of that figure.

Fig. 9 is a schematic drawing to illustrate the method and means of pairing each digit of the multiplier with each digit of the multiplicand to actuate the multiplying units for deriving all the partial products of two numbers simultaneously.

Fig. lll is a schematic drawing to illustrate the method of combining the present invention with a sensing unit, integrator and accumulator unit, and a punch to provide a complete multiplying machine for punched data cards.

Fig. 11 is a sample multiplication of a four digit multiplicand by a four digit multiplier to show the method of digit pairing and marshalling of the partial products.

Referring now to the drawings, Fig. illustrates a. schematic combination of a complete punched data card multiplying machine. Briey, the machine comprises a sensing unit 20, a plurality of multiplying units 2l, which will be described in detail hereinafter, an integrator 22. and a punch 23. The sensing unit may contain any one of the sensing mechanisms now known to the art and its function is to sense the multiplier and multiplicand and transmit their values to the multiplying unit. The multiplying unit 2l receives the digit actuations and produces a series of partial products which must be added together to produce the final product. For a ten by ten multiplying machine, which has the facilities for handling a multiplier and multiplicand of ten digits each. there will be a total of one hundred partial products.

A The partial products, comprising a possible 200 digits. are received by the integrator unit 22 and added together in their proper denominational orders to produce the product. The nal product is then sent to the punch 23 where it may be used to control the punching of a data card.

The multiplying mechanism in a ten b'y ten" multiplier contains one hundred small multiplying units 24, the mechanical details of which are shown in Figs. 1, 3, 4, and 5. The unit comprises a metallic base member 25, on which is secured aseries of rod-like insulator strips 26, equally spaced to form a series of nine channels into which are placed nine multiplicand rods 21. The multiplicand rods 21 are made of insulating strips 28 with a metallic conductive base 30 which extends for the entire length of the rods 21 and forms a conductive path to the base 25. At spaced intervals a portion of the metallic base is bent upward to form a lug 3i, each rod having i8 lugs along its length.

' A series of retaining screws 32, secured to the base at each end thereof, holds the rods 21 inplace and, because of a slot 33, restricts the motion of the rods to a predetermined range.

` Above the plane of the multiplicand rods and at right angles thereto ls mounted a series of nine multiplier rods 34. These rods are slidably mounted by means of retaining screws in a manner similar to rods 21. Each rod has mounted on it a series of I8 contact fingers 31,

in spaced relation, held securely by a rivet 3B.

The lower end of the contact spring is formed into a spherical surface so that the contact spring 5 can slide over the surface of the insulator and into contact with the lugs 3i. The upper end of the contact finger extends vertically above the rod surface so that a connecting wire may be soldered to it to provide a path for an electrical circuit as will be described hereinafter. To insure the mechanical stability of the fingers as they are moved into and out of contact with the lugs, each linger is tted into a slot 40 cut in the side of rod 34.

When the multiplying unit is in operation, it is set up in an arrangement which holds all the rods in the no-contact position by spring pressure. When a partial product is desired, one oi the multiplier rods 34 is moved to contact position and one of the multiplicand rods is also moved to contact position. This condition is illustrated in Fig. 3 where parts of two multiplicand rods and two multiplier rods are shown. The lower multiplicand rod 21 is shown in its actuated position having been moved to the right as far as the slot 33 permits and the lugs 3l thereon have been moved to a position where they are in line with the rounded contact points of fingers 31.

The right hand multiplier rod 34 is shown in its actuated position, having been lowered so that the contact fingers 31 are in line with all the lugs. At one, and only one, position two contact fingers make electrical contact with two lugs and the currents through these two contacts select two electromagnets to control the designation of a units digit and a. tens digit to complete the partial product.

The electrical wiring of the multiplying unit is shown in Fig. 2'. A battery 4I has its positive terminal connected to a. line 42 which is connected to two series of l1 electromagnets; a units series 43, designated from 1 to 9 and a tens series 44, designated from 1 to 8. The negative 46 terminal of the battery 4| is shown connected to one of the contact terminals in each of 8l contact assemblies. Actually such connection is made to the metallic conducting base 25 (see Figs. 4 and 5) and is thereby distributed to all the lugs 3l 60 to give the same result as indicated in the wiring diagram.

In the diagram of Fig. 2 each contact assembly is represented by one or two contacts, and each such position is designated by a product. The

upper horizontal row is numbered from 1 to 9 to represent the product of any multiplier digit by one. The left hand vertical row is numbered from 1 to 9 to represent the product of any multiplicand digit by one. All the other product designations are determined by multiplying the corresponding number at the top of the row with the number at the left of the row. Each multiplying unit contains 8| contact assemblies, representing all the products resulting from the multiplication of two digits from i to 9, inclusive.

The diagram of connections (Fig. 2) shows only those contacts that are necessary to obtain the product and for a. number of products only one pair of contacts is required, such as 1X6 or 4X5. The drawings of Figs. l, 3, 4, and 5 show double lcontacts (two lugs and two contact springs) for each contact assembly because in practice it has been found easier to make all multiplier rods and multiplicand rods with the same number of components, thereby simplifying the process of manu- 5 facture and the ease of servicing. Where' only" onecontact isneeded instead of two, both cont'actiingers are connected together.

The wiring is so arranged that when the contacts of any one position are made, current ows" from the battery 41' through the left hand contact points to one of the solenoids in the tens series 44 and through the right hand contact points to one of the'solenoids in the units series 43. it be assumed that a 6 is sensed in the multiplier` and a B'is sensed in the multiplicand. Then the. sixth multiplier rod and the third multiplicand rod are actuated and the only contacts that'areI made thereby are the two Acontacts 65 designated by the product 185 The left hand contact makes a circuit which may be traced from the battery di, over conductor 46, then overV con" ductor 41, to the bottom portion of contact position 45. through the left hand contact point,

over conductor 48, to conductor 5U, thence by to the first solenoid in the tens conductor 5I series M and back to the battery 4i by way of conductor 42.

The right hand contact point also makes a circuit which may be traced lfrom the battery di over conductors 4B and 41 as before 'to the contact position 45, then through the right hand contact finger and over'conductor 52. conductor 53, to a solenoid in the units series 43, designated as 1'8" and from there back to the positive terminal of battery 4l by way of common conductor 42.

The result of the above series of connections is to cause the actuations of solenoids designated as the product "18 when a"6 and a 3 are' multiplied together. The armatures of the solenolds (not shown)y are connected to an integrator which adds all the partial products together.

However, the products derived from the actionf of the multiplying boards may be used for any statistical purpose desired.

In order to multiply two numbers, each having aplilrality of digits. in a small interval of time,

all the partial products should be determined as soon as practicable after the Sensing mechanism has sensed the values. This requirement may be met by using the same number of multiplying units as is obtained by multiplying the number of digits in the multiplier by the number of digits in the multiplicand. For a ten by ten" machine, one hundred units will be required. In

To illustrate the operation-of the unit, left the description that follows a "four by four" machine is used as an example in order to describe the mechanisms and operation with as little complication as possible. are necessary for the four by four machine and they are mounted parallel to each other ln a cage which enables the sensing mechanism to actuate the multiplying unit rods in accordance with the requirements of multiplication.

Figs. 6 and 8 illustrate scheme of mounting the units. A base 51 supports plates 58 and 60 at one side of the cage and between the latter plates a series of spring pressed members 6l are mounted` nine for each multiplying unit. A similar set of spring members 62 is mounted below the multiplying units by means of a horizontal perforated plate G3 and two vertical sideplates E4 and B5. A pair of grooved rods 66 and 61 are mounted on plate 63 to hold the sixteen multiplying units in spaced relation and in proper register for the actuating levers.

To the left of spring pressed members 62 is a thiol: plate 68 which supports a series of thirty-- six balls 1li. The balls are pivoted on four shafts Sixteen multiplying units l' fourniultiplier rods onine) bywnionth, nioveineiits or the oai1 are.

Y condones-'aridmejseieoieaiiiiinipiior rods alare' actuated. The" tensore. contronos byooiitroi arojsecurea-to the pase pistoia] iii 'grigio vertical position. O ne end'of 'each corilsrlolrotl 13 engages a'multiplier'rbd'34 While th'other end is engaged cya Bowden-wire iug 11; The Bowden wire ter'- minals 1B are secured ,in a ytiiticiail plate 80 which is suitably secured to the 4 'base'plate 51. The Bowden' wires; control rods 413; multiplier rods 3l. aridbails 1D are all resilie'ntly hld in their nonactuated position by the Spring members 6I. The purpose of the hails is tojroperlydistribute the actuating impulses 'received from the sensing unit soA that eacn'digirortne multiplier is paired with each digit of the 'muitipiicana Accordingly there are four series of nine Bowden wires running f r'm the seisine'unitto-tl'1c'plat B0- Eh BOW- deri wire actuaires a control rdjl which' in tinn moves a baii'in. Eaon'baiiji controls three other co "trol rods 413 'so that when a Slgle actuation ofj a' Bowden wire ls y 3 4 "are moved to their actuated position'. The drawing'Figl` 8 ilustrates howV the action Eis distributed.' If ctrl rod 13 is actuated, thencontlol rods 13b, 13d, and 13d are also actuated because the ballllis' 'engaged by the projections 14 oith'ese particular control rods. In yorder to distribute 'the strains of actuation equally along the 4 i:iails, the '.Bowden wires are mounted ln the central portion of the plate B0 and engage those control rds`13`that are within the dotted line 8 I.

VSil serve as guide plates, with'the necessary pei-- forations, to guide the'vertical motion of a pl-urality of forkeddistributors 9 2. A top plate 93 holds terminal 84 of the Bowden wires. The wires, distributors 92 and multiplicand rods 21 are all resilientlyheld in their non-actuated position by the spring members 62,

Fig.` 9 shows the method Ofdigit pairing in a schematic representation. In this figure the multiplier units 24 are indicated by a series of dot- 'ted lines, the multiplicand distributors 92 are schematically shown as controlled by nine keys foreach order, and the multiplier balls are indicated by a series of lines connected with controlling keys.

In order to consider the operation of the systern of multiplier units, let it be assumed that a multiplicand, 2,345 ls to be multiplied by a multiplier 6,789. (See Fig. 11.) The multiplicand is entered into the cage 82 by the actuation of the designated forked distributors 92. In the thousands order the second distributor will be actuated and hence the second multiplicand rod in the first four multiplying units will be lowered.

VIn the hundreds order the third distributor and "the third multiplicand rod in each of the next 1li which, nts into-the noie inf l. Thecohtrf'ol rods are slidably and 16 which' madeafour control rods and four units will be actuated, and in a similar manner, the fourth distributor in the tens order and the fifth in the units.

On the multiplier side in the thousands order, the sixth Bowden Wire and the sixth bail will be actuated causing four multiplier rods to be moved. The representation of these rods is indicated by a cross in circles 95 in Fig. 9, the circles occurring in the rst of each of the four units 2l as divided into orders by the multiplicand.

In the hundreds order a 7 is entered into four units, shown in Fig. 9 by crosses in circles 96. And in a similar manner an "8 in the tens order and a 9 in the units order are entered into their respective units as indicated.

At the bottom of the drawing the factors are listed adjacent to the multiplying unit in which they are entered. A comparison of these paired factors and the sample multiplication in Fig. 11 shows that the correct combination of all factors is represented. Fig. l1 also shows the familiar marshalling of the product digits in their proper orders to be added by the integrator into the final product.

In the foregoing description one set of multiplying rods was designated as multiplier" and another set as "multiplicand" These designations were made to make the description more clear and understandable; actually either set of rods or either number used in the example might have either designation because the partial products are all formed at the same time and none of the sequence operations, which usually identify both multiplier and multiplicand, were present.

AWhile there have been described what are at present considered to be the preferred embodiments of this invention, it will be obvious to those skilled in the art that various changes and modifications may be made therein without departing from the invention.

I claim:

1. A partial products mechanism for producing the product of two digits comprising, a plurality of multiplier rods movably mounted in parallel relationship, each of said rods corresponding to a digit, a pluralityof multiplicand rods movably mounted in parallel relationship, each of said rods corresponding to a digit. mechanical limit means for restricting the rod motion to an actuated or an unactuated position, a plurality of contact fingers secured to each of said multiplier rods in spaced relation thereon, each iinger representing a product digit, a plurality of contact lugs secured to each of said multiplicand rods in spaced relation thereon, a base structure for slidably holding said multiplicand rods which comprises channels for the rods and intermediate rod-like strips for sliding engagement by the multiplier fingers, a plurality of electromagnetic coils, each corresponding to a product digit, for transmitting product values to an integrating mechanism, and electrical connectingmeans joining all contact fingers of similar product-digit value with the electromagnetic coil having a corresponding value.

2. A partial products mechanism for producing the product of two digits comprising, a plurality of multiplier rods movably mounted in parallel relationship, each of said rods corresponding to a digit, a plurality of multiplicand rods movably mounted in parallel relationship, each of said rods corresponding to a digit, mechanical limit means for restricting the rod motion to an actuated or an unactuated position, a plurality of contact lingers secured to each of said multiplier rods in spaced relationship thereon, each finger representing a product digit, a plurality of contact lugs secured to each of said multiplicand rods in spaced relationship thereon, actuating means for moving any one of said multiplier rods to its actuated position where electrical contact may be made by said lingers, actuating means for moving any one of said multiplicand rods to its actuated position where electrical contact may be made by said lugs, a base structure for slidably holding said multiplicand rods which comprises channels for the rods and intermediate rod-like strips for sliding engagement by the multiplier fingers, a plurality of electromagnetic coils, each corresponding to a. product digit, for transmitting product values to an integrating mechanism, and electrical connecting means joining all contact lingers of similar product-digit Value with the electromagnetic coil having a corresponding value.

3. A partial products mechanism for producing the product of two digits comprising, nine multiplier rods movably mounted in parallel relationship, nine multiplicand rods movably mounted in parallel relationship, each of said multiplier rods and multiplicand rods corresponding to a digit from one to nine, mechanical limit means for restricting the rod motion to an actuated or an unactuated position, a plurality of contact ngers secured to each of said multiplier rods in spaced relationship thereon, each finger representing a product digit, a plurality of contact lugs secured to each of said multiplicand rods in spaced relationship thereon, actuating means for moving any one of said multiplier rods to its actuated position where electrical contact may be made by said fingers, actuating means for moving any one of said multiplicand rods to its actuated position where electrical contact may Vbe made by said lugs, a base structure for slidably holding said multiplicand rods which comprises channels for the rods and intermediate rod-like strips for sliding engagement by the multiplier ngers, a plurality of electromagnetic coils, each corresponding to a product digit, for transmitting product values to an integrating mechanism, and electrical connecting means joining all contact fingers of similar product-digit value with the electromagnetic coil having a corresponding value.

4. A partial products mechanism for producing the product of two digits comprising, nine multiplier rods movably mounted in parallel relationship, nine multiplicand rods movably mounted in parallel relationship, each of said multiplier rods and multiplicand rods corresponding to a digit from one to nine, mechanical limit means for restricting the rod motion to an actuated or an unactuated position, a plurality of contact fingers secured to each of said multiplier rods in spaced relationship thereon, each finger representing a product digit, a plurality of contact lugs secured to each of said multiplicand rods in spaced relationship thereon, actuating means for moving any one of said multiplier rods to its actuated position where electrical contact may be made by said fingers, actuating means for moving any one of said multiplicand rods to its actuated position where electrical contact may be made by said lugs, said contact fingers on the multiplier rods so disposed as to complete a circuit through the lugs on the multiplicand rods only when one of each rods is in the actuated position and then only at the point of crossing of the two actuated rods, a base structure for slidably holding said multiplicand rods which comprises channels for the rods and intermediate rod-like strips for sliding engagement by the multiplier fingers. a plurality of electromagnetic coils, each corresponding to a product digit, for transmitting product values to an integrating mechanism, and electrical connecting means joining all contact lingers of similar product-digit value with the electromagnetic coil having a. corresponding value.

5. A partial products mechanism for producing the product of two digits comprising, nine multiplier rods movably mounted in parallel relationship, nine multiplicand rods movably mounted in parallel relationship, each of said multiplier rods and multiplicand rods corresponding to a digit from one to nine, mechanical limit means for restricting the rod motion to an actuated or an unactuated position, a plurality of contact fingers secured to each of said multiplier rods in spaced relationship thereon, each iinger representing a product digit, a plurality of contact lugs secured to each of said multiplicand rods in spaced relationship thereon, actuating means for moving any one oi said multiplier rods to its actuated position where electrical contact may be made by said fingers, actuating means for moving any one of said multiplicand rods to its actuated position Where electrical contact may be made by said lugs, said contact lingers on the multiplier rods so disposed as to complete a circuit through the lugs on the multiplicand rods only when one of each rods is in the actuated position and then only at the point of crossing of the two actuated rods, a base structure for slidably holding said multiplicand rods which comprises a base plate of conducting material and rod-like insulator strips secured to the base plate to form channels for said multiplicand rods, the top surfaces of the rods and strips forming a substantially plane surface for sliding engagement by the multiplier contact nngers, a plurality of electromagnetic coils, each corresponding to a product digit, for transmitting product Values to an integrating mechanism, and electrical connecting means joining all contact fingers of similar product-digit value with the electromagnetic coil having a corresponding value.

6. A partial products mechanism for producing the product of two digits comprising, nine multiplier rods movably mounted in parallel relationship. nine multiplicand rods movably mounted in parallel relationship, each of said multiplier rods and multiplicand rods corresponding to a digit from one to nine, mechanical limit means for restricting the rod motion to an actuated or an unactuated position, a plurality of contact fingers secured to each of said multiplier rods in spaced relationship thereon. each nger representing a product digit, a plurality of contact lugs secured to each of said multiplicand rods in spaced relationship thereon, actuating means for moving any one of said multiplier rods to its actuated position where electrical contact may be made by said ngers, actuating means for moving any one of said multiplicand rods to its actuated position where electrical contact may be made by said lugs, said contact iingers on the multiplier rods so disposed as to complete a circuit through the lugs on the multiplicand rods only when one of each rods is in the actuated position and then only at the point of crossing of the two actuated rods, a base structure for slidably holding said multiplicand rods which comprises a base plate of conducting material and rod-like insulator strips secured to the base plate to form channels for said multiplicand rods. the top surfaces of lil the rods and strips forming a substantially plane surface for sliding engagement by the multiple contact iingers, each of said rods containing one contact where the product may be expressed by a single digit and containing two contacts where the product requires two digits, a plurality of electromagnetic coils, each corresponding to a product digit, for transmitting product values to an integrating mechanism, and electrical connecting means Joining all contact fingers of similar product-digit value with the electromagnetic coil having a corresponding value.

'7. A partial products mechanism for producing the product of two digits comprising, nine multiplier rods movably mounted in parallel relationship, nine multiplicand rods movably mounted in parallel relationship, each of said multiplier rods and multiplicand rods corresponding to a digit from one to nine, mechanical limit means for restricting the rod motion to an actuated or an unactuated position, a plurality of contact ngers secured to each of said multiplier rods in spaced relationship thereon, each finger representing a product digit, a plurality of contact lugs secured to each of said multiplicand rods in spaced relationship thereon, actuating means for moving any one of said multiplier rods to its actuated position where electrical contact may be made by said fingers, actuating means for moving any one of said multiplicand rods to its actuated position where electrical contact may be made by said lugs, said contact fingers on the multiplier rods so disposed as to complete a circuit through the lugs on the multiplicand rods only when one of each rods is in the actuated position and then only at the point of crossing of the two actuated rods, a base structure for slidably holding said multiplicand rods which comprises a base plate of conducting material and rod-like insulator strips secured to the base plate to form channels for said multiplicand rods, the top surfaces of the rods and strips forming a substantially plane surface for sliding engagement by the multiple contact lingers, each of said rods containing one contact Where the product may be expressed by a single digit and containing two contacts where the product requires two digits, a series of seventeen electromagnets, nine corresponding to the units product digits and eight corresponding to the tens product digits from one to eight, inclusive, and a plurality of electrical circuits connecting said electromagnets with corresponding contact ngers on the multiplier rods, the lugs on said multiplicand rods, and a source of electrical power.

RALPH E. BITNER.

REFERENCES CITED The following references are of record in the le of this patent:

UNITED STATES PATENTS Number Name Date 1,374,366 Dickerson Apr. 12, 1921 1,886,148 Baumann et al Nov. 1, 1932 2,296,276 Gollwitzer Sept. 22, 1942 2,362,702 Krieger Nov. 14, 1944 2,403,480 Clary July 9, 1946 FOREIGN PATENTS Number Country Date 581,788 France Oct. 2, 1924 350,920 Italy July 26, 1937 

